As of now I have a 1999 F-150 with drum brakes in the back. I'm looking to convert them to disc brakes but the conversion kit is around $500 or so from what I've seen online. So here are a couple of my questions:

I have the off road/tow package and I'm not sure if I have a limited slip rear end. When I jack up the truck and spin the rear tires, they spin in the opposite direction. Is there any other way to tell if the diff is open or LS?

Also, how do I know what gears i have? I tried making a mark on one tire and the drive line and I got all screwed up so there must be a tag some where and its in Ford code so I can't read it.

So, I will potentially be looking for a rear end with disc brakes and LS. What are my chances of finding one of these in Washington state at a decent price? What should I expect to pay? I found a rear axle on ebay minus the LS for a couple hundred.

My last question has to do with installing a disc brake conversion on my current rear end. How hard is the install and how much is braking improved?

I'm sure I'll come up with a few more questions so any help is appreciated!

 

I am also looking to swap in an axle from my dad's 99 f150, 5.4 V8 w/ tow package, which has the LS and disc brakes, and was wondering how hard it would be switch my axle with his, especially the brakes, because that seems like the biggest problem. I am hoping i can use the stock brake lines on both trucks when i swap the entire axle assembly.

 

There are codes in the door jam that tell you what the axle you have (ratio and LS or not). Do a search here there is a link that will decipher it for you but there have been several posts with the info as well. You can't tell a LS by the way the wheels turn when jacked up because there won't be a diffenence between the force on the wheels to engage the clutch so it will appear to be open (wheels spin in oposite directions). As for swapping axles I think the biggest problem would likely be the proportioning valve. It may be a different split for the 4 wheel disks than the drums. I'm not sure about line sizes and that is just a general observation I have made over the years. I haven't done one of these trucks yet.

Hope that helps you out.

 

what exactly is the proportioning valve and where is it? If they are different, couldn't those just be swapped along with the axle, keep the valves with the axles?

 

If you plan on driving in mud and dirt roads frequently, I would advise against going with the disc brakes. They are notorious for getting crud and grit into the calipers and grinding down your pads and rotors, and you will have to replace them twice as often as your front brakes. I've run into this problem with my wife's work van, and it's not off-highway too much, maybe about five miles a day on ordinary dirt roads. Also, GM is going back to drums on their P/U's because of this very problem, so unless you plan on washing the calipers often it's not worth it.

 

Ive had the exact opposite experience actually, b/c my dad's pickup spends A LOT of time offroad, basically a farm pickup and spends quite a bit of time in the mud and dirt, sand, etc. and have never had any problems with the rear disc brakes, its actually the front disc brakes that are having problems, as i had to replace the rotors and pads because the were grinded down from dirt and sand, but we have never had that problem with the rear disc brakes

 

I've replaced three rear rotors on the van since we bought it two years ago, and the pads three times, due to the buildup of crud on the calipers. I've only changed the front pads twice. Maybe the pickups are different, I dunno, b/c I don't take mine off-highway that often. But I do know that our local tire shop changes out rotors on different manufacturers p/u's on a daily basis because of this problem, and as I said, GM is going back to drums because of this. If I had the choice between drums or discs on the back of the van, it would be drums in a heartbeat.